Connecting external SCSI devices

Connecting external SCSI devices

This section explains how to connect external devices such as external hard disk drives, MO drives, or CD-ROM drives.

About SCSI

SCSI (pronounced “scuzzy”) stands for Small Computer System Interface, and is a data transmission interface standard used by personal computers and other devices.

Since the MOTIF has a SCSI interface, you can connect and use hard disk drives, MO disk drives, CD-ROM drives, and other SCSI-compatible devices that have a 50-pin SCSI connector. Up to 7 SCSI devices can be connected.

Most external SCSI devices have two SCSI terminals, allowing a number of devices to be “chained” together. Devices chained together in this way can normally be connected in any order.

The last device in the chain must be “terminated,” either with a terminator unit plugged into the open SCSI connector, or by turning the device's internal terminator on (if available). The first device in the chain must also be terminated, but in the case of the MOTIF this is accomplished by the terminator inside the MOTIF.

External SCSI

 

External SCSI

 

 

External SCSI

 

device

 

device

 

 

device

 

 

 

 

 

 

T

 

 

 

 

 

 

T

T Indicates the terminator (or a terminator switch turned ON). For devices not marked by this symbol, do not attach a terminator (or turn the terminator off).

MOTIF

Appendix

•Before connecting SCSI devices, be sure to turn off the power of the MOTIF and all connected equipment. If the power is on while connections are being made, the MOTIF or SCSI devices can be damaged.

•Including the MOTIF, each SCSI device is distinguished by a number from 0 - 7, called the SCSI ID. If two or more devices have the same SCSI ID number, the SCSI devices will not function correctly. When shipped from the factory, the MOTIF is set to SCSI ID 6. Be aware that the SCSI ID number of a device has no relation to its position in the daisy-chain.

•Don't forget to attach a terminator to the last SCSI device in the daisy-chain.

•If an external SCSI device is not connected, it is not necessary to attach a terminator to the external SCSI connector of the

MOTIF.

•Use as short a SCSI cable as possible. Using long cables can cause unreliable operation. In general, the total cable length should be less than 6 meters (approximately 18 feet).

•Use high-quality SCSI cables. Poor-quality cables can cause unreliable operation.

•Some SCSI devices have only one SCSI connector. If you are using such a device, connect it at the end of the daisy-chain.

Procedure

1 Use SCSI cables to daisy-chain the external SCSI devices.

Since there are several different types of SCSI connectors, make sure to select the proper SCSI cables for your particular devices.

2 Connect the power cable of the external SCSI device to an AC outlet.3 Set the SCSI ID (0 - 7) of the external SCSI device.

Select a SCSI ID that will not conflict with the other SCSI devices (including the MOTIF). When the MOTIF is shipped from the factory, the SCSI ID is set to 6.

290MOTIF Appendix